All Questions
Tagged with typescript mapped-types
354
questions
1
vote
1
answer
31
views
Using string literal as a reference to named interface
I got multiple interfaces, say Int1, Int2 and so on
interface Int1 {}
interface Int2 {}
And I want to create a registry, structured as
const Registry = {
"Int1": {
"obj1": {}...
- 63
1
vote
1
answer
44
views
Flatten mapped type to intersection removing the iterated union' keys used to create it
I am not sure how to better phrase the question but I hope the question title with the code below is self-explanatory, despite it might seem useless.
EDIT reduced code to the bare minimum:
type ...
- 485
0
votes
0
answers
35
views
Resolve Generic of Generic
I'm trying to create a reusable utility type in TypeScript that works with any map type conforming to a generic structure. Here's my basic setup:
type SomeMap<T> = {
[key: string]: T;
};
I ...
- 23
0
votes
2
answers
46
views
Can the type of a type parameter be inferred from the entries of an Array?
In the following example, is it possible for the type of P to be inferred from the entries in the props array, rather than having to define it twice?
type A = {
one: boolean
two: number
three: ...
- 4,484
0
votes
0
answers
47
views
Why does `[K in (keyof typeof SomeNumericEnum) as typeof SomeNumericEnum[K]]` result in the actual numerical index, rather than just `number`?
Given the following enum:
enum Animals {
CAT,
DOG,
PARROT,
SHEEP,
SALMON
}
The following mapped type:
type AnimalsToMappedType = {
[K in (keyof typeof Animals) as typeof Animals[K]]: K
}
...
- 4,484
2
votes
1
answer
65
views
Why does adding parentheses remove 'readonly [x: number]: number;' from this type?
enum Animals {
CAT,
DOG,
PARROT,
SHEEP,
SALMON
}
The following type:
type AnimalsToMappedType = {
[K in keyof typeof Animals]: K
}
Results in:
type AnimalsToMappedType = {
readonly [x: ...
- 4,484
0
votes
1
answer
36
views
How can I apply TS Conditional types, Mapped Types on this method?
I'm working with a TypeScript class that represents a form with various input types. Each input class has a getValue() method that returns different types based on the input. I need to create a type ...
- 26
2
votes
2
answers
56
views
How to generically set values of mapped type
See this following code example:
type Properties = {
item0: { item0: string };
item1: { item1: string };
item2: { item2: string };
item3: { item3: string };
item4: { item4: string };
};
...
- 1,740
0
votes
2
answers
28
views
In TypeScript how might one create a mapped, conditional type that removes properties of type string | null
Here's my final failed attempt before coming here for advice. What am I doing wrong pls ty?
interface Something {
id: string;
name: string | null;
}
interface AnotherThing {
id: string;
name: ...
- 2,494
4
votes
0
answers
25
views
Do mapped types magically detect `null` and `undefined`? [duplicate]
If I can trust my vscode transpiler it tells me that for each of these types the result is the one I put in comments
type keyOfNull = keyof null // never
type keyOfundefined = keyof ...
- 13.1k
0
votes
2
answers
36
views
Create a RecursivePartializer
I have the following typescript code
type Bar = {
foo: string;
prop: number;
baz: {
value: string;
check: boolean;
}
}
I want to create a mapped type such that
type ...
- 9,714
1
vote
1
answer
58
views
Is there a way to infer the keys of a mapped type when using Typescript?
I have a data structure that represents my business operations:
const operations = {
list: {
request: "a",
response: "b",
},
get: {
request: &...
- 30.2k
1
vote
1
answer
118
views
Another TS 5.4 regression (i think).... how to go about fixing this type in 5.4
Recent Typescript changes (5.4.x, everything worked in 5.3.3) have made some regressions which caused a number of issues. The first one I posted about HERE.
The fix proposed in that other post does ...
- 1,506
2
votes
1
answer
60
views
How to refactor long union type?
I want to create a React functional component which takes one of the predefined components as a prop and which logic depends on what component was passed in.
So these are the possible names:
enum ...
- 593
1
vote
1
answer
76
views
TypeScript mapped types: from list of both objects and strings to a key-value object
I'm trying to write a mapped type that takes a list which can contain both objects ("definitions") and strings. String values are limited to a set of strings that refer to existing hard ...
- 125